Glyphosate impairs learning in mosquito larvae (Aedes aegypti) at field-realistic doses

Abstract

Glyphosate is the most widely used herbicide in the world. In the last years, the number of studies revealing deleterious effects of glyphosate on non-target species has been increasing. We studied the impact of glyphosate at field-realistic doses on learning in mosquito larvae (Aedes aegypti). Larvae of A. aegypti live in small water bodies and perform a stereotyped escape response when a moving object projects its shadow on the water surface. Repeated presentations of an innocuous visual stimulus induce a decrease in response due to habituation, a non-associative form of learning. In this study, different groups of larvae were reared in water containing different concentrations of glyphosate that can be found in the field (50 µg/l, 100 µg/l, 210 µg/l and 2 mg/l). Larvae reared in a glyphosate solution of 2 mg/l could complete their development. However, glyphosate impaired habituation. The higher the dose, the stronger the deleterious effects on learning abilities. This protocol opens new avenues to further studies aiming at understanding how glyphosate affects non-target organisms as insects. Habituation in mosquito larvae could serve as a parameter for testing the impact of pollutants in water bodies.